


a bolt of blue

by oryx



Category: Kamen Rider Build
Genre: Attempted Coercion, M/M, Possession, Trans Male Character, the villain using the heroes' pure feelings for his own sketchy purposes
Language: English
Status: Completed
Published: 2018-06-01
Updated: 2018-06-01
Packaged: 2019-05-16 20:33:56
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,327
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14818394
Author URL: https://archiveofourown.org/users/oryx/pseuds/oryx
Summary: Evolt tries a different tactic.





	a bolt of blue

**Author's Note:**

> evolt!sento could've been so much more than it was, is all i'm saying.  
> ryuga being trans is really only a quick vague implication here, but. that is my hc for him so i'm using the tag anyhow.

  
“You know,” that voice says. “There’s so many things I could do to him, right this very moment.”  
   
Ryuga’s grip tightens around the phone. His shoulders ache from tensing them. It’s only been a day and he already can’t remember what it’s like, to not feel like this – like he’s standing on thin ice that’s splintering bit by bit beneath his feet.  
   
“But,” Evolt continues, as conversational as someone commenting on the weather, “I’m just not really in the mood for threats today, honestly. So instead, I have an offer for you, Ryuga-kun. You bring me the Pandora Box, and I give you… an exciting opportunity.”  
   
“I don’t want any opportunities from you,” Ryuga growls.  
   
“No? I’d rather give you the specifics face-to-face, but I can tell you now that it’s a more than fair trade. Won’t you at least hear me out? Or I might really have to resort to threats, and neither of us want that.” He doesn’t wait to hear an answer before adding: “I’ll text you my location. And come alone, ple-ase.” He draws out that word in a way that sets Ryuga’s teeth on edge. “Those other two would only get in the way. Ciao!”  
   
The  _click_  of him hanging up echoes in Ryuga’s ear as he turns back to look at Kazumi and Gentoku.  
   
“So?” Kazumi says searchingly. “What’s that bastard want now? Just the box?”  
   
“I guess so,” Ryuga mutters. His phone buzzes, and he taps the screen to find not just an address but an entire street map sent from Sento’s number, the marked location a government office building a few blocks from where they are now. He’s fairly sure it’s been shut down since the war started.  
   
“Oi, Kazumin,” he says, after a moment of hesitation. “Can you… guard the box for a bit? I’m gonna go meet with him.”  
   
“Wha – by yourself? Don’t screw with me.”  
   
“He said he’d give me an opportunity,” Ryuga says hotly. “And it’s probably bullshit, but. If I can spin it to save Sento, or at least… Help him, maybe. I dunno. Not like we have a whole lot of options here.” He scrubs a hand across his face; takes a deep breath. He feels like he’s fraying around the edges. “I’ll call if things go south. Alright? Just. Let me try.”  
   
Kazumi ‘tch’s under his breath. He hangs his head with a tired sigh before glancing back up at him. “Guess it’s pointless to try stopping you. Just… don’t let him get to you. Especially with that face.”  
   
“As if I would,” Ryuga protests, with far more confidence in his voice than he feels.  
   
_It’s not Sento_ , he tells himself, and repeats the thought again and again like a mantra.  
   
No matter what, it’s not Sento.  
   
  
   
  
   
He finds Not Sento on the third floor of the building amid the grey rows of empty desks, swiveling back and forth in one of the abandoned office chairs. The fluorescent auxiliary lighting turns his hair an even more sterile white.  
   
“There you are,” he says, lifting a hand to wave, but it falters a moment later, his expression turning sour. He purses his lips. “Ryuga-kun, I asked for one simple thing. The b-o-x. And yet you don’t seem to have it. Funny, that.”  
   
“Like hell I would just bring it to you no questions asked,” Ryuga snaps. “Not until you tell me what you’re offering in exchange.”  
   
Evolt sighs dramatically. “Oh, fine.” He hops to his feet, and there’s something so Sento-like about the motion that Ryuga feels a twist in his chest. “Honestly, the offer is pretty simple. You help me now, and soon enough, when this world is destroyed… I’ll spare your life and Sento’s.”  
   
Ryuga blinks.  
   
“…Haa?”  
   
“Of course,” Evolt continues, “you two will be the only exceptions. Everyone else is still going to die. But you’re pretty reasonable, Ryuga-kun. You’re not a complete bleeding heart martyr like everyone’s favorite genius here.” He taps Sento’s chest. “What’s that little slogan of yours…? That you fight for those you believe in, and those who believe in you? Well. The world as a whole has never believed in you. But Sento has. Between saving him and dying pointlessly trying to save everyone else… The choice seems pretty obvious, if you ask me.”  
   
Ryuga feels like someone has just wrapped a cold hand around his heart and squeezed it tight. His voice sounds hoarse when he says: “That’s – you really think I’d just agree to that?”  
   
Evolt arches an eyebrow. “Why not? What has the world ever done for Sento, either? He’s been through a lot, hasn’t he? And did the world ever appreciate it? Did they ever care about his – what was it again… ‘Love~ and~ peace~’?”  
   
Here he flashes a V for victory, striking a pose with a smile, and in an instant white hot rage is slamming into Ryuga like a punch to the gut. It burns at the back of his neck. He’s closing the distance between them before he can think twice to slap Evolt’s hand down, twisting his fingers into the collar of Sento’s shirt.  
   
“You don’t get to say that,” he grits out.  
   
Evolt’s small smile doesn’t falter. Sento’s irises have a faint unearthly reddish glow to them as he tilts his head to the side. “Am I wrong, though? You were a little out of commission at the time, so maybe you missed the details, but. He went out there to  _die_  yesterday, you know. No question. He knew exactly what would happen to him. And it would’ve, except for one tiny malfunction.”  
   
There is a buzzing in Ryuga’s ears. Evolt’s words sound like they’re being spoken from a great distance. “To die?” he echoes, his grip on Sento’s collar gradually loosening until his hand falls away, limp at his side.  
   
He’d been shuttered away in a corner of his mind, then, watching his own actions in disjointed snippets, but he’d seen enough, heard enough to feel the truth behind Evolt’s words. Maybe he’d been trying to ignore it.  
   
Is it a surprise, really? That Sento would pull something like that? And yet it’s the certainty of it that’s rattling him. At least with the Hazard Trigger it was only a possibility, a worst case scenario. That stunt yesterday, he’s now realizing, had been an outright suicide run.  
   
“Mm-hmm. That was the plan,” Evolt is saying. “You would’ve woken up and both he and I would’ve just been… gone.” He makes a gesture reminiscent of a puff of smoke vanishing. “Frankly I’ve been a little angry about it. Him throwing a wrench into my plans like that. But then I got to thinking. About how long it’s been since I had an opponent who offered me any kind of challenge. It would be a shame, wouldn’t it? To just let you two die, when you’ve both exceeded my expectations.”  
   
Ryuga swallows hard. “…So, what?” he hears himself say. “I say yes, and we get left alone on a world that’s all been wiped out? Your pitch here kinda sucks.”  
   
“Obviously not,” Evolt scoffs. “Use your head for once, Ryuga. I’m saying you two would come with me. When I leave for the next hunt.”  
   
Ryuga stares at him.  
   
There’s an old wall clock somewhere on this floor; he can hear it ticking steadily in the long stretch of silence.  
   
“What,” he says finally.  
   
Evolt hums, contemplative. “The thing is, until you’ve experienced the total annihilation of a planet firsthand, watching from above knowing nothing can harm you, you can’t possibly know. About the feeling you get. None of your human words can really do it justice. …‘Transcendent,’ maybe? Hunting planets is as natural to me as breathing is to you, and it  _still_  gets me every time. The magnitude of it.” Sento’s eyes are eerily bright, suddenly, excitement bleeding through in Evolt’s voice. “Those final few moments when it’s like the roaring climax of a symphony.”  
   
Ryuga’s fingers are digging into his palm. “Your point?”  
   
Evolt seems to come down a bit from whatever rapturous thoughts he was just entertaining, his expression smoothing again. “I’m saying that you boys are very opposed to the destruction of Earth right now, but… When you actually see it, I think you’ll understand. And you’ll want to see it again.”  
   
“We’re not like you,” Ryuga says, baring his teeth in a scowl.  
   
“So you keep informing me,” Evolt says dryly. He steps around Ryuga, circling slowly behind him, and Ryuga freezes when he feels fingers trailing light across his shoulders. “But at the end of the day, even without any of my power remaining in you, you’re still a part of me. I’d be willing to give a bit back to you, you know. If we were allies. Enough that you could walk the stars with me. And Sento… Well. Let’s just say no mere human should have ever been able to hit a Hazard Level of six, Pandora Box or no. He’s got the potential to be even more than he already is. Something immortal.”  
   
Ryuga is staring pointedly at the floor, a tight, tense feeling in his throat. He can see the toes of Sento’s mismatched sneakers as Evolt comes to a halt in front of him again.  
   
“Banjou,” Sento’s voice says.  
   
Ryuga’s pulse skips as he snaps his head up. The reddish glow is gone from Sento’s eyes. He’s looking at him without any of Evolt’s menace, his expression soft and so very tired.  
   
“…Sento?”  
   
He should know better than to hope. He remembers Evolt using his own voice to catch Sento off guard, but this seems different, somehow. This seems –  
   
“Maybe it would be better,” Sento says, “if you just accepted the offer.”  
   
“…What?”  
   
The corner of Sento’s mouth curves into a weary smile. “I think… I’m worn out, Banjou. Aren’t you? What can we do, if that last attempt didn’t work? If even the direct power of the Pandora Box wasn’t enough to end this? At this point,” and here he lifts a hand, reaching out, fingertips brushing his cheek as Ryuga sucks in a breath, “maybe, as long as you’re still alive when all this is over… That’ll be good enough for me.”  
   
Something drops like a stone in the pit of Ryuga’s stomach. No, he thinks. This isn’t Sento.  
   
Knowing that, he wonders why can’t bring himself to pull away.  
   
“It wouldn’t be so bad, would it?” Not Sento gives him a searching look. His hand slides back to curl around the nape of his neck, and the place where his palm is touching feels lit up. “You and me, living together forever. Even if everyone else is gone. You know… that I need you more than anyone, right? Ryuga.”  
   
The sound of his name is like a long, thin knife being shoved between his ribs. He watches half in a daze as Not Sento steps closer, mouth parted as he leans in, and Ryuga can’t tear his eyes away from the pink of his lips.  
   
Their lips are almost brushing when Ryuga comes back to himself with a start. He puts his hands on his shoulders; shoves him away and stumbles backwards, breath coming quick and ragged. His heartbeat is loud in his ears.  
   
“You – don’t use his body for weird shit,” he hisses.  
   
Forgoing his bad impression, Evolt’s expression shifts back into his usual callousness as he rolls his eyes. He switches back to his own voice and says: “You two are beyond hopeless, you know that?”  
   
“…What’s that supposed to mean?”  
   
“I mean I wouldn’t be using his body for anything he didn’t want. And I’ve been inside your mind, too. I know all the desperate  _feelings_  floating around in there. You boys would be a lot happier if you just  _told_  each other this stuff, you know.” He shakes his head. “Honestly, it’s a miracle the human race has survived as long as it has, what with how bad at communication you all are. I’m doing you people a favor by putting you out of your self-induced misery.”  
   
Ryuga’s mouth feels dry. “That’s,” he starts. “That’s not…”  
   
Just another of Evolt’s lies, he tells himself. Sento is so much better than him. So much brighter that it’s like being blinded, sometimes. He knows Sento thinks of him as an important ally. But anything more than that is. Just a stupid dream.  
   
“What, don’t believe me? You should really work on that self-esteem, partner.”  
   
He takes a step closer again, and Ryuga finds himself unconsciously backing up. Another step, another retreat, until the backs of his knees hit something solid and his balance gets knocked askew, falling with a  _thump_  into what turns out to be an old leather armchair behind him.  
   
He’s trapped, then. And he feels it, too – like an animal in the lights of an incoming car. Evolt moves nearer still, looking down at him through Sento’s eyelashes, and he seems to ponder for a moment before slotting a knee against Ryuga’s side and swinging his other leg over to straddle his lap.  
   
Ryuga goes very still. Sento’s weight against him feels good, his thighs warm against his own, and he squeezes his eyes shut, stomach churning. The discomfiting mix of pleasure and nausea only intensifies as he feels those fingers absentmindedly playing with his hair.  
   
“I’ll admit,” Evolt muses, “that last attempt at being Sento wasn’t really me trying my hardest. If I was really going for believability, maybe I’d do something… like this?"  
   
“You’re an idiot, Banjou,” Sento’s voice says.  
   
Despite himself, Ryuga opens his eyes.  
   
His expression this time is unmistakably Sento-like – exasperated and fond and very slightly arrogant.  
   
“We’ve been stuck together ever since we first met, haven’t we?” He lifts a hand and splays it on Ryuga’s chest, just above his heart. “I can’t seem to get rid of you, no matter what I do. And I guess… I’ve always liked persistent people.” He shrugs a shoulder, an air of faux nonchalance. “So it’s only logical, that I’d end up feeling the same. Even if you are a musclebrain.”  
   
His hand slides down his chest, running his fingertips over the slight raise of the scars beneath the fabric of his shirt, and Ryuga suddenly can’t breathe.  
   
“And you’re even more of an idiot,” he continues, voice soft, “if you think a brilliant man of science like myself would care about this.”  
   
That hand around Ryuga’s heart squeezes again – once, twice. He wonders why he feels like crying.  _It’s not him_ , he tells himself over and over. He’s not the one saying this.  
   
“Stop it,” he says weakly.  
   
Not Sento sighs. “You always have to make things difficult, don’t you? I’m trying to be honest here.”  
   
His hands drift up to cup Ryuga’s face. His eyes are indistinguishable from Sento’s, in this moment, with that same inquisitive glint. It all feels so genuine as he leans in to kiss him – lingering and slow and dizzyingly warm, Ryuga making a choked noise against his lips, his grip painfully tense around the arms of the chair as he tries not to reach for him.  
   
Not Sento is smiling as he pulls away, leaving only a few inches between them. “See?” he says. “That wasn’t so hard.”  
   
His hand trails down the line of Ryuga’s throat, skimming over his collarbone, fingers dipping beneath the collar of his shirt –  
   
And it’s then that his other hand snakes out to grab his own wrist and yank himself back.  
   
Genuine surprise is written across his face as he stares down at it. The left hand is trembling, white-knuckled, its grip tight enough that red marks are already forming against the skin of Sento’s wrist.  
   
“No way,” Not Sento murmurs. His voice is faltering – a trace of Evolt bleeding through. When he laughs, it’s a sharp, unhinged sound. “It took Isurugi eight years to manage that. And you… in a single day…” He hangs his head, and when he lifts it again the guise of Sento is forgotten once more, a subtle anger to Evolt’s crooked grin. “Sento… You really are pissing me off. Why can’t you just be good, hm? Why can’t you obey your creator?”  
   
Ryuga listens to this with his heart in his throat. This, at least, can’t possibly be a ploy. Can it? It’s rare to hear such legitimate rage simmering beneath the surface of Evolt’s voice.  
   
He seizes the opportunity and shoves Evolt off of him, Evolt stumbling a bit, Sento’s wrist still caught in a self-induced death-grip. Ryuga jumps to his feet and backs away, breathing hard and keeping his eyes trained on Sento’s face. It seems to shift again and again between two opposite expressions before settling on the latter – strained and desperate.  
   
“Banjou,” Sento says through gritted teeth, and somehow, instinctively, Ryuga just knows.  
   
“Sento,” he breathes. He goes to step back towards him, reaching out a hand, but Sento shakes his head.  
   
“Don’t. I can’t do this for long. Just… I know you’re not such an idiot. That you’d let him manipulate you. But you,” and here he licks his lips, “you know which parts were true, don’t you?”  
   
Ryuga halts in place. He can feel his eyes widen.  
   
“Once this is over,” Sento says, looking at him with a quiet intensity, “I’ll say it myself.”  
   
And then in an instant he is gone, Evolt’s barely-disguised fury snapping back into place as if a switch had just been flipped. He straightens his posture, rolling Sento’s shoulders with an aggravated exhale.  
   
“How romantic,” he deadpans. “I’m really in a bad mood now, but how about this: I’ll give you one last chance to say yes to my offer, Ryuga-kun.”  
   
Something aches in his chest, but Ryuga finds himself smiling, just a bit. “As if I would,” he says. “You’ve just been wasting your time, asshole.” A beat. “Maybe… I still don’t totally get it. This Kamen Rider thing. If it was just up to me, I  _would_  pick him over the whole world. But. I know he’d hate me for it, if I did. And I know what he’d choose. And I still want to try. To be someone like that.”  
   
Evolt stares at him blankly before making a frustrated noise, running Sento’s fingers through that shock of white hair. “You two… You’re unbelievable. I give you a mile and you won’t even take an inch. We could’ve been great together, you know.” Here he sobers, the disappointment in his voice sounding strangely real. “The three of us. We could’ve seen the whole universe. Could’ve put out the lights in the sky one by one.  
   
“But no. You just won’t give up your stupid little ideals. When are you going to realize that it’s too late? That there’s nothing you  _can_  do anymore. And you just tossed your last chance of survival out the window.” He shakes his head, lips pressed together in a thin line. “Forget it. I guess I’ll have to add an ‘or else’ into this after all. Bring me the Pandora Box at the plaza by the amphitheater,” he says, enunciating each word sharply. “Or I can’t promise what might happen to your boyfriend.”  
   
His smile is cold and joyless as a tear in the fabric of the world opens up and swallows him, leaving Ryuga alone on the empty office floor.  
   
He lets out a shaky breath. Tiredness washes over him like a wave, sinking beneath his skin and weighing him down. He sinks down slowly to crouch there on the floor, sitting back on his heels, staring up at the dull patterning of the industrial ceiling tiles.  
   
_Once this is over, I’ll say it myself._  
   
“You better,” he says out loud, speaking into the silence and feeling like a fool the next moment later as his own voices echoes back at him. His eyes sting, and he hastily blinks it away.  
   
Time for Plan B, then.


End file.
